CSS Clamp Generator

Generate a fluid, responsive CSS clamp() value from a minimum and maximum size and viewport, with px or rem units and a live preview of the formula.

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Build a fluid, responsive CSS clamp() value in seconds with this free CSS clamp generator. Enter a minimum size at a small viewport and a maximum size at a large viewport, pick px or rem, and the tool works out the linear formula so your font sizes, spacing, and widths scale smoothly between breakpoints — no media queries required. Copy a ready-to-paste clamp() rule, all computed right in your browser.

      

        
What is a CSS clamp generator?

        
A CSS clamp generator builds the clamp() function for fluid, responsive sizing. clamp() takes three values — a minimum, a preferred value, and a maximum — and the browser picks the preferred value as long as it stays between the bounds. The tricky part is the preferred value, which mixes a fixed amount with a viewport-relative vw amount. This tool calculates that formula for you from two size-and-viewport pairs so the result scales linearly between your chosen breakpoints and then locks at the limits.

        
      

      

        
How to generate a clamp() value

        
Describe the smallest and largest sizes you want and the viewport widths where each should apply. The generator fills in the rest and updates live.

        
  1. Choose px or rem, and set the root font size if you use rem.
  2. Enter the minimum size and the viewport width where it should apply.
  3. Enter the maximum size and the viewport width where it should apply.
  4. Read the live preview line to confirm how the value scales.
  5. Click Copy CSS to grab the ready-to-paste clamp() rule.

      

      

        
Why use this CSS clamp generator?

        
  • Computes the exact preferred value (constant + vw) for you — no manual math.
  • Works in px or rem and converts cleanly using your root font size.
  • Outputs a single clamp() rule that replaces stacks of media queries.
  • Live preview explains how the value scales between viewports.
  • Great for fluid typography, spacing, gaps, and container widths.
  • 100% free and private — everything runs in your browser.

      

      

        
Frequently asked questions

        

          
What does CSS clamp() do?

          
clamp(min, preferred, max) returns the preferred value as long as it stays between the minimum and maximum. Below the lower viewport it sticks at the minimum, above the upper viewport it sticks at the maximum, and in between it scales smoothly. It is the cleanest way to make a value fluid without media queries.

        

        

          
How is the preferred value calculated?

          
The generator finds the straight line through your two size-and-viewport points. The slope becomes a vw value (because 1vw is 1% of the viewport width) and the remainder becomes a fixed offset, giving a preferred value like 1rem + 2.5vw that hits your minimum at the small viewport and your maximum at the large one.

        

        

          
Should I use px or rem in clamp()?

          
rem is usually best for font sizes because it respects the user's browser font-size setting, which helps accessibility. px is fine for fixed spacing or borders. This tool lets you switch units and uses your root font size to convert between them accurately.

        

        

          
Does clamp() replace media queries?

          
For a single value that should scale with the viewport — like a heading size, section padding, or grid gap — clamp() replaces a chain of breakpoint overrides with one line. You may still want media queries for layout changes such as switching from one column to two.